Arduinna-class battleship

Class overview
Name:	Arduinna-class battleship
Operators:	Royal Ossorian Navy
Preceded by:	Dian Cécht-class
Succeeded by:	Aífe-class
In commission:	1932 - 1964
Planned:	6
Completed:	6
Retired:	6
General characteristics
Type:	Battleship
Displacement:	43,320 t standard 46,974 t full load
Length:	235 meters
Beam:	33 meters
Draught:	10 meters
Propulsion:	8 x 8 3-drum small-tube boilers 4 x geared turbines 4 x screws
Speed:	28 kts
Range:	7,000 nm at 14 kts
Complement:	1,553
Armament:	10 x 380 mm/45 caliber guns 16 x twin 120 mm/45 caliber dual-purpose guns 40 x quad 40 mm/55 caliber anti-aircraft guns 40 x single 20 mm/70 caliber anti-aircraft guns
Armor:	Belt: 370 mm Deck: 150 mm Gun: 300 mm Barbette: 300 mm Bulkhead: 300 mm Conning tower: 100 mm

The Arduinna-class was a class of six fast battleships built for the Royal Ossorian Navy starting in 1930. The class comprised of the ships Arduinna, Danu, Áengus, Niamh, Branwen, and Dáire.

Design

General characteristics

The Arduinna-class ships were 235 metres long overall, had a beam of 33 m and a draught of 10 m with a normal displacement of 45,350 t. The ships were powered by four screws powered by four turbines driven by steam provided by eight 3-drum small-tube oil-fired boilers. The engines were rated at approximately 126,000 shaft horsepower and delivered a top speed of 28 knots. Arduinna and her sisters were capable of a maximum range of 7,000 nautical miles at a cruising speed of 14 knots.

Armament

The Arduinna-class ships mounted a main battery of ten 38 cm breach-loading guns mounted in two four-gun turrets fore and aft and a single two-gun turret behind and above the fore turret, ("Beith" and "Luis" turrets forward and "Nion" turret aft). The gun housings allowed for the guns to depress to −5° and elevate to 40°. The gun turrets could train 270° in either direction from the centreline. The guns could fire 875 kg shells at a rate of approximately 1.5 rounds per minute, and were capable of firing a variety of shells. At their maximum elevation of 40°, the guns had a range of approximately 30,000 m.

The Arduinna-class was the only Royal Navy battleship class to forego using all two-gun turrets for the main battery, partly in an effort to fit more guns into a hull of reduced tonnage, and partly in response to the Syaran Navy's recent use of four-gun turrets in their Makedon-class and Zovahr-class battleships. In practice, the Navy regarded the unorthodox layout to be overly prone to malfunction due to the necessary mechanical complexities required to operate the guns. While corrections were eventually made which reduced the rate of malfunctions, the Navy ultimately reverted back to two-gun turrets with the Aífe-class and Lugh-class battleships.

The secondary battery consisted of sixteen 12 cm dual-purpose guns mounted in twin turrets amidships. These guns fired 25 kg shells at a rate of approximately 12 rounds per minute. The guns could elevate to 80°, which enabled a maximum range of 19,000 m.

Armor

The Arduinna-class ships had an all or nothing armor layout, with its armor belt that was 370 mm thick in the central area of the ship (covering the ammunition magazines, machinery spaces, and other vital parts of the ship) leaving the fore and aft sections of the side hull unarmored. The main gun turrets were 300 mm on the sides and 75 mm on the rear, where shells were less likely to hit. The barbettes in which the turrets sat were 300 mm thick. The ships' armored deck was 150 mm thick.

Ships

Ship	Namesake	Builder	Laid down	Launched	Commissioned	Fate
Arduinna	Goddess of Hunting	HRM Dockyard, Gabhrán	1927	1928	1932
Danu	Goddess of Creation	HRM Dockyard, Thiar	1927	1928	1932
Áengus	God of Strength	HRM Dockyard, Cléire	1927	1928	1933
Niamh	Goddess of Dawn	HRM Dockyard, Thiar	1927	1929	1933
Branwen	Goddess of Love	HRM Dockyard, Gabhrán	1928	1929	1933
Dáire	God of Warfare	HRM Dockyard, Cléire	1928	1929	1933